Field
The methods and systems described herein generally relate to enhanced fiber optic cleaning and inspection methods and systems.
Description of the Related Art
In fiber optic systems, it is important to provide very low losses of light at junctions between fibers and other optical devices, while retaining the flexibility of field interconnections. As a result, the end faces of fiber optic connectors must be smoothly polished to reduce scratches that scatter light and cleaned to remove contaminants and particles that block or scatter light. To verify the optical quality of the end face of the fiber optic connector, the fiber optic connector is cleaned and then inspected. Given that fibers have cores that can range in size from approximately 7 micron to 3 mm, very small defects can contribute to unacceptable losses so that the cleaning and inspection processes must be capable of reliably removing and detecting micron sized defects. For ease of handling and proper alignment, fibers are typically mounted into a ferrule that is larger and more durable. Ferrules can include multiple fibers such as for fiber arrays. The ferrule is typically mounted into a connector for connecting to another ferrule with mating fiber optics. The ferrule and connector must be cleaned and inspected after the fibers have been mounted. In addition to inspecting the fiber end faces, some standards and customers require the inspection of the ferrule region for contamination and/or scratches. This inspection requires a much larger (up to a few millimeters) Field of View, but generally at slighter lower resolution than is required for the fiber end face inspection.
In arrays of fibers, the inspection system needs to be able to locate the fibers within the ferrule to assist the inspection process. Typically an optics based search method along with known dimensional information associated with the ferrule is used to locate the fibers. However, given the large size of the ferrule relative to the size of the fiber, the magnification and field of view of the optics used to find the fiber is different from the optics used to characterize the defects on the fiber end. Cleaning can be performed before or after the fibers have been found. In an automated process, the method for finding the fibers, cleaning the fibers and then identifying defects can determine the speed and efficiency of the inspection process.
U.S. Pat. No. 7,837,801 describes a method and apparatus for cleaning an optical fiber using a cleaning wipe. A variety of cleaning techniques using cleaning wipes are disclosed. Automated inspection is not included with the automated cleaning.
United States Patent publication 2011/0085159 provides a handheld fiber optics inspection probe with a lens and a camera with autofocus to capture an image of the fiber optic. Cleaning is not provided along with the inspection probe and the inspection probe is not automated for inspecting arrays of fiber optics. Because the inspection probe is handheld, a single set of optics is provided and the finding of the fiber is left to the operator.
United States Patent publication 20040125366 discloses a system for automated inspection of fiber. The system includes mechanisms to automatically center, focus a lens, and capture images of ends of fiber optics to assess defects that are present. The inspection system can be combined with a cleaning system on a portable cart to clean the fiber optics prior to inspection. However, the cleaning and inspections systems are not connected so that recontamination is possible. In addition, the system does not include a way to automatically identify the positions of the fibers, instead the system relies on input dimensions. The use of lower magnification optics to provide a wider field of view for finding the fibers is not discussed.
United States Patent publication 20110150395 describes an automated system for fiber severing to cut the fibers in a connector to the same length to prepare the connector for polishing. Wherein the relative position of the ends of the fiber optics is inferred by determining the positions of the ferrule shoulders surrounding the fiber optics using a camera and image analysis. The system provided uses a video camera located at the side so that length of the fibers can be determined; as such this camera system is not capable of investigating defects on the ends of the fibers.
Therefore there remains a need for an improved method for performing automated finding of fiber end faces, cleaning of the fiber end faces, fiber optic connector or other fiber optic components and inspection for defects in a fast and efficient manner.